Readers' comments

The reason there is so much opposition to expansion at Heathrow is the noise nuisance. Therefore, why not just prohibit all flight from 10pm to 7am weekdays and 9pm to 8am at weekends. This would satisfy the opposition and allow Heathrow to expand.

Or is it a case of the third runway having a flight path over Kensington, where there are many vested interests who enjoy a good nights sleep?

At the costs you quote for the estuary option you could build a rail tunnel between heathrow and stansted and/or gatwick. Running trains at 300 km/h the travel time would be under 15 minutes - less than the time it currently takes between terminals at heathrow.

I agree. A tunnel would cost more, but still less than a new airport. I suggested the tunnel option because cutting a transport corridor through north west london is likely to create even more opposition than an extra runway. Options with a tunnel include maglev, pneumatic etc.

Tokyo responded to its capacity shortage at Narita Airport by expanding Haneda to 4 runways, and expanding Shinkansen network to take load off domestic flights and make way for international flights out of Haneda.
If Runway 3 is not an option, the British government would be wise to expedite HS2, and ask JR East about how to construct and operate HSR trains on conventional rail (Current operator of the Javelin in Kent would be rated a failure in Japan)

Applying the Tokyo method to London, BAA could also consider adding 3 runways simultaneously to Gatwick, and turning Gatwick into a hub. This will put most of London outside the approach routes, AND minimize migration costs of airlines. [Haneda airports' 4 runways were all built from scratch on a newly reclaimed land or newly built pier. New Haneda airport opened with 2 runways, simultaneously scrapping the old one, then the third runway was built by relocating the old runway B closer to the new site shortly afterward, and the fourth runway was completed only a couple of years ago, at the same time as the International Terminal.]

“A hundred years ago London had the best infrastructure in the world. Its legacy is historically impressive but sometimes difficult to manage. Single-track Tube tunnels mean that breakdowns bring a line to a halt; curved tunnels and platforms, shaped by the Victorians’ inability to dig through the hardest rock, slow the system down”

The Victorian engineers who built the tube system under London did not have to drive tunnels through hard rock as in New York but through London Clay using tunnelling shields invented by Alfred Greathead. The curved platforms and sharp radius curves arose as tube promoters followed the medieval street grid of London in order to avoid paying way leaves to land owners.

Mwmbwis is completely correct.
The idea that "curved tunnels and platforms" were "shaped by the Victorians' inability to dig through the hardest rock" may be plausible to the layman, but is fallacious. There is virtually no rock directly below the surface of London, let alone hard rock.
Having worked underground on the Victoria Line extension in the late 1960s, I can attest from first hand experience that the predominant soil is London blue clay, which has the consistency of a very hard cheese. I was involved in one of the last significant stretches of Tube line (including a crossing of the Thames) to be dug by hand, rather than by tunneling machines. Our tunnel miners cut their way through the clay using hand-held pneumatic spades.
It is also worth noting that much of the tunnel was built on curves, necessary to align with existing surface features as Mwmbwis correctly points out.

4 runways at Heathrow remove the dyfunctional performance and add some capacity for the weather.

The Wimbledon Tennis is similar to the about change debates. No money needed for Heathrow as would be able to be financed. Modern politics is the new dysfunctionality.

Heathrow exapansion is a bargain opportunity. Other options are not affordable as the appetite of London for deep tubes and Crossrail 2 and 3 and for other relief scheme is not possible in a wider stagnent UK. Infrastructure in cities and in capital cities is too expensive.